yes stators are diff in efi than in carb and timing is diff from yr to yr so say a 02 zl has less timing than a 03 zl and the computer from the o2 would have to be used if dropped dropped in to the o3.cat will re flash a box for under 40 bucks.did you drop a crank?the 600 is not known for that.if not why not just new or re nicked jugs